#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 110;
int n;
ll x[N], y[N];

ll d(int i, int j) {
    return (x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]);
}
int main() {
#ifdef LOCAL
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
#endif
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> x[i] >> y[i];
    }

    ll mmax = -1;
    double res = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = i + 1; j <= n;j++) {
            if (d(i, j) > mmax) {
                mmax = d(i, j);
                res = sqrt(mmax * 1.0);
            }
        }
    }
   printf("%.7lf\n", res);
    return 0;
}